1 /*
2 * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "compiler/compileLog.hpp"
27 #include "opto/addnode.hpp"
28 #include "opto/callGenerator.hpp"
29 #include "opto/callnode.hpp"
30 #include "opto/divnode.hpp"
31 #include "opto/graphKit.hpp"
32 #include "opto/idealKit.hpp"
33 #include "opto/rootnode.hpp"
34 #include "opto/runtime.hpp"
35 #include "opto/stringopts.hpp"
36 #include "opto/subnode.hpp"
37
38 #define __ kit.
39
40 class StringConcat : public ResourceObj {
41 private:
42 PhaseStringOpts* _stringopts;
43 Node* _string_alloc;
44 AllocateNode* _begin; // The allocation the begins the pattern
45 CallStaticJavaNode* _end; // The final call of the pattern. Will either be
46 // SB.toString or or String.<init>(SB.toString)
47 bool _multiple; // indicates this is a fusion of two or more
48 // separate StringBuilders
49
50 Node* _arguments; // The list of arguments to be concatenated
51 GrowableArray<int> _mode; // into a String along with a mode flag
52 // indicating how to treat the value.
53
54 Node_List _control; // List of control nodes that will be deleted
55 Node_List _uncommon_traps; // Uncommon traps that needs to be rewritten
56 // to restart at the initial JVMState.
57 public:
58 // Mode for converting arguments to Strings
59 enum {
60 StringMode,
61 IntMode,
62 CharMode,
63 StringNullCheckMode
64 };
65
66 StringConcat(PhaseStringOpts* stringopts, CallStaticJavaNode* end):
67 _end(end),
68 _begin(NULL),
69 _multiple(false),
70 _string_alloc(NULL),
71 _stringopts(stringopts) {
72 _arguments = new (_stringopts->C) Node(1);
73 _arguments->del_req(0);
74 }
75
76 bool validate_control_flow();
77
78 void merge_add() {
79 #if 0
80 // XXX This is place holder code for reusing an existing String
81 // allocation but the logic for checking the state safety is
82 // probably inadequate at the moment.
83 CallProjections endprojs;
84 sc->end()->extract_projections(&endprojs, false);
85 if (endprojs.resproj != NULL) {
86 for (SimpleDUIterator i(endprojs.resproj); i.has_next(); i.next()) {
87 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
88 if (use != NULL && use->method() != NULL &&
89 use->method()->intrinsic_id() == vmIntrinsics::_String_String &&
90 use->in(TypeFunc::Parms + 1) == endprojs.resproj) {
91 // Found useless new String(sb.toString()) so reuse the newly allocated String
92 // when creating the result instead of allocating a new one.
93 sc->set_string_alloc(use->in(TypeFunc::Parms));
94 sc->set_end(use);
95 }
96 }
97 }
98 #endif
99 }
100
101 StringConcat* merge(StringConcat* other, Node* arg);
102
103 void set_allocation(AllocateNode* alloc) {
104 _begin = alloc;
105 }
106
107 void append(Node* value, int mode) {
108 _arguments->add_req(value);
109 _mode.append(mode);
110 }
111 void push(Node* value, int mode) {
112 _arguments->ins_req(0, value);
113 _mode.insert_before(0, mode);
114 }
115
116 void push_string(Node* value) {
117 push(value, StringMode);
118 }
119 void push_string_null_check(Node* value) {
120 push(value, StringNullCheckMode);
121 }
122 void push_int(Node* value) {
123 push(value, IntMode);
124 }
125 void push_char(Node* value) {
126 push(value, CharMode);
127 }
128
129 static bool is_SB_toString(Node* call) {
130 if (call->is_CallStaticJava()) {
131 CallStaticJavaNode* csj = call->as_CallStaticJava();
132 ciMethod* m = csj->method();
133 if (m != NULL &&
134 (m->intrinsic_id() == vmIntrinsics::_StringBuilder_toString ||
135 m->intrinsic_id() == vmIntrinsics::_StringBuffer_toString)) {
136 return true;
137 }
138 }
139 return false;
140 }
141
142 static Node* skip_string_null_check(Node* value) {
143 // Look for a diamond shaped Null check of toString() result
144 // (could be code from String.valueOf()):
145 // (Proj == NULL) ? "null":"CastPP(Proj)#NotNULL
146 if (value->is_Phi()) {
147 int true_path = value->as_Phi()->is_diamond_phi();
148 if (true_path != 0) {
149 // phi->region->if_proj->ifnode->bool
150 BoolNode* b = value->in(0)->in(1)->in(0)->in(1)->as_Bool();
151 Node* cmp = b->in(1);
152 Node* v1 = cmp->in(1);
153 Node* v2 = cmp->in(2);
154 // Null check of the return of toString which can simply be skipped.
155 if (b->_test._test == BoolTest::ne &&
156 v2->bottom_type() == TypePtr::NULL_PTR &&
157 value->in(true_path)->Opcode() == Op_CastPP &&
158 value->in(true_path)->in(1) == v1 &&
159 v1->is_Proj() && is_SB_toString(v1->in(0))) {
160 return v1;
161 }
162 }
163 }
164 return value;
165 }
166
167 Node* argument(int i) {
168 return _arguments->in(i);
169 }
170 Node* argument_uncast(int i) {
171 Node* arg = argument(i);
172 int amode = mode(i);
173 if (amode == StringConcat::StringMode ||
174 amode == StringConcat::StringNullCheckMode) {
175 arg = skip_string_null_check(arg);
176 }
177 return arg;
178 }
179 void set_argument(int i, Node* value) {
180 _arguments->set_req(i, value);
181 }
182 int num_arguments() {
183 return _mode.length();
184 }
185 int mode(int i) {
186 return _mode.at(i);
187 }
188 void add_control(Node* ctrl) {
189 assert(!_control.contains(ctrl), "only push once");
190 _control.push(ctrl);
191 }
192 CallStaticJavaNode* end() { return _end; }
193 AllocateNode* begin() { return _begin; }
194 Node* string_alloc() { return _string_alloc; }
195
196 void eliminate_unneeded_control();
197 void eliminate_initialize(InitializeNode* init);
198 void eliminate_call(CallNode* call);
199
200 void maybe_log_transform() {
201 CompileLog* log = _stringopts->C->log();
202 if (log != NULL) {
203 log->head("replace_string_concat arguments='%d' string_alloc='%d' multiple='%d'",
204 num_arguments(),
205 _string_alloc != NULL,
206 _multiple);
207 JVMState* p = _begin->jvms();
208 while (p != NULL) {
209 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
210 p = p->caller();
211 }
212 log->tail("replace_string_concat");
213 }
214 }
215
216 void convert_uncommon_traps(GraphKit& kit, const JVMState* jvms) {
217 for (uint u = 0; u < _uncommon_traps.size(); u++) {
218 Node* uct = _uncommon_traps.at(u);
219
220 // Build a new call using the jvms state of the allocate
221 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
222 const TypeFunc* call_type = OptoRuntime::uncommon_trap_Type();
223 const TypePtr* no_memory_effects = NULL;
224 Compile* C = _stringopts->C;
225 CallStaticJavaNode* call = new (C) CallStaticJavaNode(call_type, call_addr, "uncommon_trap",
226 jvms->bci(), no_memory_effects);
227 for (int e = 0; e < TypeFunc::Parms; e++) {
228 call->init_req(e, uct->in(e));
229 }
230 // Set the trap request to record intrinsic failure if this trap
231 // is taken too many times. Ideally we would handle then traps by
232 // doing the original bookkeeping in the MDO so that if it caused
233 // the code to be thrown out we could still recompile and use the
234 // optimization. Failing the uncommon traps doesn't really mean
235 // that the optimization is a bad idea but there's no other way to
236 // do the MDO updates currently.
237 int trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_intrinsic,
238 Deoptimization::Action_make_not_entrant);
239 call->init_req(TypeFunc::Parms, __ intcon(trap_request));
240 kit.add_safepoint_edges(call);
241
242 _stringopts->gvn()->transform(call);
243 C->gvn_replace_by(uct, call);
244 uct->disconnect_inputs(NULL, C);
245 }
246 }
247
248 void cleanup() {
249 // disconnect the hook node
250 _arguments->disconnect_inputs(NULL, _stringopts->C);
251 }
252 };
253
254
255 void StringConcat::eliminate_unneeded_control() {
256 for (uint i = 0; i < _control.size(); i++) {
257 Node* n = _control.at(i);
258 if (n->is_Allocate()) {
259 eliminate_initialize(n->as_Allocate()->initialization());
260 }
261 if (n->is_Call()) {
262 if (n != _end) {
263 eliminate_call(n->as_Call());
264 }
265 } else if (n->is_IfTrue()) {
266 Compile* C = _stringopts->C;
267 C->gvn_replace_by(n, n->in(0)->in(0));
268 // get rid of the other projection
269 C->gvn_replace_by(n->in(0)->as_If()->proj_out(false), C->top());
270 }
271 }
272 }
273
274
275 StringConcat* StringConcat::merge(StringConcat* other, Node* arg) {
276 StringConcat* result = new StringConcat(_stringopts, _end);
277 for (uint x = 0; x < _control.size(); x++) {
278 Node* n = _control.at(x);
279 if (n->is_Call()) {
280 result->_control.push(n);
281 }
282 }
283 for (uint x = 0; x < other->_control.size(); x++) {
284 Node* n = other->_control.at(x);
285 if (n->is_Call()) {
286 result->_control.push(n);
287 }
288 }
289 assert(result->_control.contains(other->_end), "what?");
290 assert(result->_control.contains(_begin), "what?");
291 for (int x = 0; x < num_arguments(); x++) {
292 Node* argx = argument_uncast(x);
293 if (argx == arg) {
294 // replace the toString result with the all the arguments that
295 // made up the other StringConcat
296 for (int y = 0; y < other->num_arguments(); y++) {
297 result->append(other->argument(y), other->mode(y));
298 }
299 } else {
300 result->append(argx, mode(x));
301 }
302 }
303 result->set_allocation(other->_begin);
304 result->_multiple = true;
305 return result;
306 }
307
308
309 void StringConcat::eliminate_call(CallNode* call) {
310 Compile* C = _stringopts->C;
311 CallProjections projs;
312 call->extract_projections(&projs, false);
313 if (projs.fallthrough_catchproj != NULL) {
314 C->gvn_replace_by(projs.fallthrough_catchproj, call->in(TypeFunc::Control));
315 }
316 if (projs.fallthrough_memproj != NULL) {
317 C->gvn_replace_by(projs.fallthrough_memproj, call->in(TypeFunc::Memory));
318 }
319 if (projs.catchall_memproj != NULL) {
320 C->gvn_replace_by(projs.catchall_memproj, C->top());
321 }
322 if (projs.fallthrough_ioproj != NULL) {
323 C->gvn_replace_by(projs.fallthrough_ioproj, call->in(TypeFunc::I_O));
324 }
325 if (projs.catchall_ioproj != NULL) {
326 C->gvn_replace_by(projs.catchall_ioproj, C->top());
327 }
328 if (projs.catchall_catchproj != NULL) {
329 // EA can't cope with the partially collapsed graph this
330 // creates so put it on the worklist to be collapsed later.
331 for (SimpleDUIterator i(projs.catchall_catchproj); i.has_next(); i.next()) {
332 Node *use = i.get();
333 int opc = use->Opcode();
334 if (opc == Op_CreateEx || opc == Op_Region) {
335 _stringopts->record_dead_node(use);
336 }
337 }
338 C->gvn_replace_by(projs.catchall_catchproj, C->top());
339 }
340 if (projs.resproj != NULL) {
341 C->gvn_replace_by(projs.resproj, C->top());
342 }
343 C->gvn_replace_by(call, C->top());
344 }
345
346 void StringConcat::eliminate_initialize(InitializeNode* init) {
347 Compile* C = _stringopts->C;
348
349 // Eliminate Initialize node.
350 assert(init->outcnt() <= 2, "only a control and memory projection expected");
351 assert(init->req() <= InitializeNode::RawStores, "no pending inits");
352 Node *ctrl_proj = init->proj_out(TypeFunc::Control);
353 if (ctrl_proj != NULL) {
354 C->gvn_replace_by(ctrl_proj, init->in(TypeFunc::Control));
355 }
356 Node *mem_proj = init->proj_out(TypeFunc::Memory);
357 if (mem_proj != NULL) {
358 Node *mem = init->in(TypeFunc::Memory);
359 C->gvn_replace_by(mem_proj, mem);
360 }
361 C->gvn_replace_by(init, C->top());
362 init->disconnect_inputs(NULL, C);
363 }
364
365 Node_List PhaseStringOpts::collect_toString_calls() {
366 Node_List string_calls;
367 Node_List worklist;
368
369 _visited.Clear();
370
371 // Prime the worklist
372 for (uint i = 1; i < C->root()->len(); i++) {
373 Node* n = C->root()->in(i);
374 if (n != NULL && !_visited.test_set(n->_idx)) {
375 worklist.push(n);
376 }
377 }
378
379 while (worklist.size() > 0) {
380 Node* ctrl = worklist.pop();
381 if (StringConcat::is_SB_toString(ctrl)) {
382 CallStaticJavaNode* csj = ctrl->as_CallStaticJava();
383 string_calls.push(csj);
384 }
385 if (ctrl->in(0) != NULL && !_visited.test_set(ctrl->in(0)->_idx)) {
386 worklist.push(ctrl->in(0));
387 }
388 if (ctrl->is_Region()) {
389 for (uint i = 1; i < ctrl->len(); i++) {
390 if (ctrl->in(i) != NULL && !_visited.test_set(ctrl->in(i)->_idx)) {
391 worklist.push(ctrl->in(i));
392 }
393 }
394 }
395 }
396 return string_calls;
397 }
398
399
400 StringConcat* PhaseStringOpts::build_candidate(CallStaticJavaNode* call) {
401 ciMethod* m = call->method();
402 ciSymbol* string_sig;
403 ciSymbol* int_sig;
404 ciSymbol* char_sig;
405 if (m->holder() == C->env()->StringBuilder_klass()) {
406 string_sig = ciSymbol::String_StringBuilder_signature();
407 int_sig = ciSymbol::int_StringBuilder_signature();
408 char_sig = ciSymbol::char_StringBuilder_signature();
409 } else if (m->holder() == C->env()->StringBuffer_klass()) {
410 string_sig = ciSymbol::String_StringBuffer_signature();
411 int_sig = ciSymbol::int_StringBuffer_signature();
412 char_sig = ciSymbol::char_StringBuffer_signature();
413 } else {
414 return NULL;
415 }
416 #ifndef PRODUCT
417 if (PrintOptimizeStringConcat) {
418 tty->print("considering toString call in ");
419 call->jvms()->dump_spec(tty); tty->cr();
420 }
421 #endif
422
423 StringConcat* sc = new StringConcat(this, call);
424
425 AllocateNode* alloc = NULL;
426 InitializeNode* init = NULL;
427
428 // possible opportunity for StringBuilder fusion
429 CallStaticJavaNode* cnode = call;
430 while (cnode) {
431 Node* recv = cnode->in(TypeFunc::Parms)->uncast();
432 if (recv->is_Proj()) {
433 recv = recv->in(0);
434 }
435 cnode = recv->isa_CallStaticJava();
436 if (cnode == NULL) {
437 alloc = recv->isa_Allocate();
438 if (alloc == NULL) {
439 break;
440 }
441 // Find the constructor call
442 Node* result = alloc->result_cast();
443 if (result == NULL || !result->is_CheckCastPP() || alloc->in(TypeFunc::Memory)->is_top()) {
444 // strange looking allocation
445 #ifndef PRODUCT
446 if (PrintOptimizeStringConcat) {
447 tty->print("giving up because allocation looks strange ");
448 alloc->jvms()->dump_spec(tty); tty->cr();
449 }
450 #endif
451 break;
452 }
453 Node* constructor = NULL;
454 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
455 CallStaticJavaNode *use = i.get()->isa_CallStaticJava();
456 if (use != NULL &&
457 use->method() != NULL &&
458 !use->method()->is_static() &&
459 use->method()->name() == ciSymbol::object_initializer_name() &&
460 use->method()->holder() == m->holder()) {
461 // Matched the constructor.
462 ciSymbol* sig = use->method()->signature()->as_symbol();
463 if (sig == ciSymbol::void_method_signature() ||
464 sig == ciSymbol::int_void_signature() ||
465 sig == ciSymbol::string_void_signature()) {
466 if (sig == ciSymbol::string_void_signature()) {
467 // StringBuilder(String) so pick this up as the first argument
468 assert(use->in(TypeFunc::Parms + 1) != NULL, "what?");
469 const Type* type = _gvn->type(use->in(TypeFunc::Parms + 1));
470 if (type == TypePtr::NULL_PTR) {
471 // StringBuilder(null) throws exception.
472 #ifndef PRODUCT
473 if (PrintOptimizeStringConcat) {
474 tty->print("giving up because StringBuilder(null) throws exception");
475 alloc->jvms()->dump_spec(tty); tty->cr();
476 }
477 #endif
478 return NULL;
479 }
480 // StringBuilder(str) argument needs null check.
481 sc->push_string_null_check(use->in(TypeFunc::Parms + 1));
482 }
483 // The int variant takes an initial size for the backing
484 // array so just treat it like the void version.
485 constructor = use;
486 } else {
487 #ifndef PRODUCT
488 if (PrintOptimizeStringConcat) {
489 tty->print("unexpected constructor signature: %s", sig->as_utf8());
490 }
491 #endif
492 }
493 break;
494 }
495 }
496 if (constructor == NULL) {
497 // couldn't find constructor
498 #ifndef PRODUCT
499 if (PrintOptimizeStringConcat) {
500 tty->print("giving up because couldn't find constructor ");
501 alloc->jvms()->dump_spec(tty); tty->cr();
502 }
503 #endif
504 break;
505 }
506
507 // Walked all the way back and found the constructor call so see
508 // if this call converted into a direct string concatenation.
509 sc->add_control(call);
510 sc->add_control(constructor);
511 sc->add_control(alloc);
512 sc->set_allocation(alloc);
513 if (sc->validate_control_flow()) {
514 return sc;
515 } else {
516 return NULL;
517 }
518 } else if (cnode->method() == NULL) {
519 break;
520 } else if (!cnode->method()->is_static() &&
521 cnode->method()->holder() == m->holder() &&
522 cnode->method()->name() == ciSymbol::append_name() &&
523 (cnode->method()->signature()->as_symbol() == string_sig ||
524 cnode->method()->signature()->as_symbol() == char_sig ||
525 cnode->method()->signature()->as_symbol() == int_sig)) {
526 sc->add_control(cnode);
527 Node* arg = cnode->in(TypeFunc::Parms + 1);
528 if (cnode->method()->signature()->as_symbol() == int_sig) {
529 sc->push_int(arg);
530 } else if (cnode->method()->signature()->as_symbol() == char_sig) {
531 sc->push_char(arg);
532 } else {
533 if (arg->is_Proj() && arg->in(0)->is_CallStaticJava()) {
534 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
535 if (csj->method() != NULL &&
536 csj->method()->intrinsic_id() == vmIntrinsics::_Integer_toString &&
537 arg->outcnt() == 1) {
538 // _control is the list of StringBuilder calls nodes which
539 // will be replaced by new String code after this optimization.
540 // Integer::toString() call is not part of StringBuilder calls
541 // chain. It could be eliminated only if its result is used
542 // only by this SB calls chain.
543 // Another limitation: it should be used only once because
544 // it is unknown that it is used only by this SB calls chain
545 // until all related SB calls nodes are collected.
546 assert(arg->unique_out() == cnode, "sanity");
547 sc->add_control(csj);
548 sc->push_int(csj->in(TypeFunc::Parms));
549 continue;
550 }
551 }
552 sc->push_string(arg);
553 }
554 continue;
555 } else {
556 // some unhandled signature
557 #ifndef PRODUCT
558 if (PrintOptimizeStringConcat) {
559 tty->print("giving up because encountered unexpected signature ");
560 cnode->tf()->dump(); tty->cr();
561 cnode->in(TypeFunc::Parms + 1)->dump();
562 }
563 #endif
564 break;
565 }
566 }
567 return NULL;
568 }
569
570
571 PhaseStringOpts::PhaseStringOpts(PhaseGVN* gvn, Unique_Node_List*):
572 Phase(StringOpts),
573 _gvn(gvn),
574 _visited(Thread::current()->resource_area()) {
575
576 assert(OptimizeStringConcat, "shouldn't be here");
577
578 size_table_field = C->env()->Integer_klass()->get_field_by_name(ciSymbol::make("sizeTable"),
579 ciSymbol::make("[I"), true);
580 if (size_table_field == NULL) {
581 // Something wrong so give up.
582 assert(false, "why can't we find Integer.sizeTable?");
583 return;
584 }
585
586 // Collect the types needed to talk about the various slices of memory
587 char_adr_idx = C->get_alias_index(TypeAryPtr::CHARS);
588
589 // For each locally allocated StringBuffer see if the usages can be
590 // collapsed into a single String construction.
591
592 // Run through the list of allocation looking for SB.toString to see
593 // if it's possible to fuse the usage of the SB into a single String
594 // construction.
595 GrowableArray<StringConcat*> concats;
596 Node_List toStrings = collect_toString_calls();
597 while (toStrings.size() > 0) {
598 StringConcat* sc = build_candidate(toStrings.pop()->as_CallStaticJava());
599 if (sc != NULL) {
600 concats.push(sc);
601 }
602 }
603
604 // try to coalesce separate concats
605 restart:
606 for (int c = 0; c < concats.length(); c++) {
607 StringConcat* sc = concats.at(c);
608 for (int i = 0; i < sc->num_arguments(); i++) {
609 Node* arg = sc->argument_uncast(i);
610 if (arg->is_Proj() && StringConcat::is_SB_toString(arg->in(0))) {
611 CallStaticJavaNode* csj = arg->in(0)->as_CallStaticJava();
612 for (int o = 0; o < concats.length(); o++) {
613 if (c == o) continue;
614 StringConcat* other = concats.at(o);
615 if (other->end() == csj) {
616 #ifndef PRODUCT
617 if (PrintOptimizeStringConcat) {
618 tty->print_cr("considering stacked concats");
619 }
620 #endif
621
622 StringConcat* merged = sc->merge(other, arg);
623 if (merged->validate_control_flow()) {
624 #ifndef PRODUCT
625 if (PrintOptimizeStringConcat) {
626 tty->print_cr("stacking would succeed");
627 }
628 #endif
629 if (c < o) {
630 concats.remove_at(o);
631 concats.at_put(c, merged);
632 } else {
633 concats.remove_at(c);
634 concats.at_put(o, merged);
635 }
636 goto restart;
637 } else {
638 #ifndef PRODUCT
639 if (PrintOptimizeStringConcat) {
640 tty->print_cr("stacking would fail");
641 }
642 #endif
643 }
644 }
645 }
646 }
647 }
648 }
649
650
651 for (int c = 0; c < concats.length(); c++) {
652 StringConcat* sc = concats.at(c);
653 replace_string_concat(sc);
654 }
655
656 remove_dead_nodes();
657 }
658
659 void PhaseStringOpts::record_dead_node(Node* dead) {
660 dead_worklist.push(dead);
661 }
662
663 void PhaseStringOpts::remove_dead_nodes() {
664 // Delete any dead nodes to make things clean enough that escape
665 // analysis doesn't get unhappy.
666 while (dead_worklist.size() > 0) {
667 Node* use = dead_worklist.pop();
668 int opc = use->Opcode();
669 switch (opc) {
670 case Op_Region: {
671 uint i = 1;
672 for (i = 1; i < use->req(); i++) {
673 if (use->in(i) != C->top()) {
674 break;
675 }
676 }
677 if (i >= use->req()) {
678 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
679 Node* m = i.get();
680 if (m->is_Phi()) {
681 dead_worklist.push(m);
682 }
683 }
684 C->gvn_replace_by(use, C->top());
685 }
686 break;
687 }
688 case Op_AddP:
689 case Op_CreateEx: {
690 // Recurisvely clean up references to CreateEx so EA doesn't
691 // get unhappy about the partially collapsed graph.
692 for (SimpleDUIterator i(use); i.has_next(); i.next()) {
693 Node* m = i.get();
694 if (m->is_AddP()) {
695 dead_worklist.push(m);
696 }
697 }
698 C->gvn_replace_by(use, C->top());
699 break;
700 }
701 case Op_Phi:
702 if (use->in(0) == C->top()) {
703 C->gvn_replace_by(use, C->top());
704 }
705 break;
706 }
707 }
708 }
709
710
711 bool StringConcat::validate_control_flow() {
712 // We found all the calls and arguments now lets see if it's
713 // safe to transform the graph as we would expect.
714
715 // Check to see if this resulted in too many uncommon traps previously
716 if (Compile::current()->too_many_traps(_begin->jvms()->method(), _begin->jvms()->bci(),
717 Deoptimization::Reason_intrinsic)) {
718 return false;
719 }
720
721 // Walk backwards over the control flow from toString to the
722 // allocation and make sure all the control flow is ok. This
723 // means it's either going to be eliminated once the calls are
724 // removed or it can safely be transformed into an uncommon
725 // trap.
726
727 int null_check_count = 0;
728 Unique_Node_List ctrl_path;
729
730 assert(_control.contains(_begin), "missing");
731 assert(_control.contains(_end), "missing");
732
733 // Collect the nodes that we know about and will eliminate into ctrl_path
734 for (uint i = 0; i < _control.size(); i++) {
735 // Push the call and it's control projection
736 Node* n = _control.at(i);
737 if (n->is_Allocate()) {
738 AllocateNode* an = n->as_Allocate();
739 InitializeNode* init = an->initialization();
740 ctrl_path.push(init);
741 ctrl_path.push(init->as_Multi()->proj_out(0));
742 }
743 if (n->is_Call()) {
744 CallNode* cn = n->as_Call();
745 ctrl_path.push(cn);
746 ctrl_path.push(cn->proj_out(0));
747 ctrl_path.push(cn->proj_out(0)->unique_out());
748 if (cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0) != NULL) {
749 ctrl_path.push(cn->proj_out(0)->unique_out()->as_Catch()->proj_out(0));
750 }
751 } else {
752 ShouldNotReachHere();
753 }
754 }
755
756 // Skip backwards through the control checking for unexpected contro flow
757 Node* ptr = _end;
758 bool fail = false;
759 while (ptr != _begin) {
760 if (ptr->is_Call() && ctrl_path.member(ptr)) {
761 ptr = ptr->in(0);
762 } else if (ptr->is_CatchProj() && ctrl_path.member(ptr)) {
763 ptr = ptr->in(0)->in(0)->in(0);
764 assert(ctrl_path.member(ptr), "should be a known piece of control");
765 } else if (ptr->is_IfTrue()) {
766 IfNode* iff = ptr->in(0)->as_If();
767 BoolNode* b = iff->in(1)->isa_Bool();
768
769 if (b == NULL) {
770 fail = true;
771 break;
772 }
773
774 Node* cmp = b->in(1);
775 Node* v1 = cmp->in(1);
776 Node* v2 = cmp->in(2);
777 Node* otherproj = iff->proj_out(1 - ptr->as_Proj()->_con);
778
779 // Null check of the return of append which can simply be eliminated
780 if (b->_test._test == BoolTest::ne &&
781 v2->bottom_type() == TypePtr::NULL_PTR &&
782 v1->is_Proj() && ctrl_path.member(v1->in(0))) {
783 // NULL check of the return value of the append
784 null_check_count++;
785 if (otherproj->outcnt() == 1) {
786 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
787 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
788 ctrl_path.push(call);
789 }
790 }
791 _control.push(ptr);
792 ptr = ptr->in(0)->in(0);
793 continue;
794 }
795
796 // A test which leads to an uncommon trap which should be safe.
797 // Later this trap will be converted into a trap that restarts
798 // at the beginning.
799 if (otherproj->outcnt() == 1) {
800 CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
801 if (call != NULL && call->_name != NULL && strcmp(call->_name, "uncommon_trap") == 0) {
802 // control flow leads to uct so should be ok
803 _uncommon_traps.push(call);
804 ctrl_path.push(call);
805 ptr = ptr->in(0)->in(0);
806 continue;
807 }
808 }
809
810 #ifndef PRODUCT
811 // Some unexpected control flow we don't know how to handle.
812 if (PrintOptimizeStringConcat) {
813 tty->print_cr("failing with unknown test");
814 b->dump();
815 cmp->dump();
816 v1->dump();
817 v2->dump();
818 tty->cr();
819 }
820 #endif
821 fail = true;
822 break;
823 } else if (ptr->is_Proj() && ptr->in(0)->is_Initialize()) {
824 ptr = ptr->in(0)->in(0);
825 } else if (ptr->is_Region()) {
826 Node* copy = ptr->as_Region()->is_copy();
827 if (copy != NULL) {
828 ptr = copy;
829 continue;
830 }
831 if (ptr->req() == 3 &&
832 ptr->in(1) != NULL && ptr->in(1)->is_Proj() &&
833 ptr->in(2) != NULL && ptr->in(2)->is_Proj() &&
834 ptr->in(1)->in(0) == ptr->in(2)->in(0) &&
835 ptr->in(1)->in(0) != NULL && ptr->in(1)->in(0)->is_If()) {
836 // Simple diamond.
837 // XXX should check for possibly merging stores. simple data merges are ok.
838 // The IGVN will make this simple diamond go away when it
839 // transforms the Region. Make sure it sees it.
840 Compile::current()->record_for_igvn(ptr);
841 ptr = ptr->in(1)->in(0)->in(0);
842 continue;
843 }
844 #ifndef PRODUCT
845 if (PrintOptimizeStringConcat) {
846 tty->print_cr("fusion would fail for region");
847 _begin->dump();
848 ptr->dump(2);
849 }
850 #endif
851 fail = true;
852 break;
853 } else {
854 // other unknown control
855 if (!fail) {
856 #ifndef PRODUCT
857 if (PrintOptimizeStringConcat) {
858 tty->print_cr("fusion would fail for");
859 _begin->dump();
860 }
861 #endif
862 fail = true;
863 }
864 #ifndef PRODUCT
865 if (PrintOptimizeStringConcat) {
866 ptr->dump();
867 }
868 #endif
869 ptr = ptr->in(0);
870 }
871 }
872 #ifndef PRODUCT
873 if (PrintOptimizeStringConcat && fail) {
874 tty->cr();
875 }
876 #endif
877 if (fail) return !fail;
878
879 // Validate that all these results produced are contained within
880 // this cluster of objects. First collect all the results produced
881 // by calls in the region.
882 _stringopts->_visited.Clear();
883 Node_List worklist;
884 Node* final_result = _end->proj_out(TypeFunc::Parms);
885 for (uint i = 0; i < _control.size(); i++) {
886 CallNode* cnode = _control.at(i)->isa_Call();
887 if (cnode != NULL) {
888 _stringopts->_visited.test_set(cnode->_idx);
889 }
890 Node* result = cnode != NULL ? cnode->proj_out(TypeFunc::Parms) : NULL;
891 if (result != NULL && result != final_result) {
892 worklist.push(result);
893 }
894 }
895
896 Node* last_result = NULL;
897 while (worklist.size() > 0) {
898 Node* result = worklist.pop();
899 if (_stringopts->_visited.test_set(result->_idx))
900 continue;
901 for (SimpleDUIterator i(result); i.has_next(); i.next()) {
902 Node *use = i.get();
903 if (ctrl_path.member(use)) {
904 // already checked this
905 continue;
906 }
907 int opc = use->Opcode();
908 if (opc == Op_CmpP || opc == Op_Node) {
909 ctrl_path.push(use);
910 continue;
911 }
912 if (opc == Op_CastPP || opc == Op_CheckCastPP) {
913 for (SimpleDUIterator j(use); j.has_next(); j.next()) {
914 worklist.push(j.get());
915 }
916 worklist.push(use->in(1));
917 ctrl_path.push(use);
918 continue;
919 }
920 #ifndef PRODUCT
921 if (PrintOptimizeStringConcat) {
922 if (result != last_result) {
923 last_result = result;
924 tty->print_cr("extra uses for result:");
925 last_result->dump();
926 }
927 use->dump();
928 }
929 #endif
930 fail = true;
931 break;
932 }
933 }
934
935 #ifndef PRODUCT
936 if (PrintOptimizeStringConcat && !fail) {
937 ttyLocker ttyl;
938 tty->cr();
939 tty->print("fusion would succeed (%d %d) for ", null_check_count, _uncommon_traps.size());
940 _begin->jvms()->dump_spec(tty); tty->cr();
941 for (int i = 0; i < num_arguments(); i++) {
942 argument(i)->dump();
943 }
944 _control.dump();
945 tty->cr();
946 }
947 #endif
948
949 return !fail;
950 }
951
952 Node* PhaseStringOpts::fetch_static_field(GraphKit& kit, ciField* field) {
953 const TypeInstPtr* mirror_type = TypeInstPtr::make(field->holder()->java_mirror());
954 Node* klass_node = __ makecon(mirror_type);
955 BasicType bt = field->layout_type();
956 ciType* field_klass = field->type();
957
958 const Type *type;
959 if( bt == T_OBJECT ) {
960 if (!field->type()->is_loaded()) {
961 type = TypeInstPtr::BOTTOM;
962 } else if (field->is_constant()) {
963 // This can happen if the constant oop is non-perm.
964 ciObject* con = field->constant_value().as_object();
965 // Do not "join" in the previous type; it doesn't add value,
966 // and may yield a vacuous result if the field is of interface type.
967 type = TypeOopPtr::make_from_constant(con, true)->isa_oopptr();
968 assert(type != NULL, "field singleton type must be consistent");
969 return __ makecon(type);
970 } else {
971 type = TypeOopPtr::make_from_klass(field_klass->as_klass());
972 }
973 } else {
974 type = Type::get_const_basic_type(bt);
975 }
976
977 return kit.make_load(NULL, kit.basic_plus_adr(klass_node, field->offset_in_bytes()),
978 type, T_OBJECT,
979 C->get_alias_index(mirror_type->add_offset(field->offset_in_bytes())));
980 }
981
982 Node* PhaseStringOpts::int_stringSize(GraphKit& kit, Node* arg) {
983 RegionNode *final_merge = new (C) RegionNode(3);
984 kit.gvn().set_type(final_merge, Type::CONTROL);
985 Node* final_size = new (C) PhiNode(final_merge, TypeInt::INT);
986 kit.gvn().set_type(final_size, TypeInt::INT);
987
988 IfNode* iff = kit.create_and_map_if(kit.control(),
989 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
990 PROB_FAIR, COUNT_UNKNOWN);
991 Node* is_min = __ IfFalse(iff);
992 final_merge->init_req(1, is_min);
993 final_size->init_req(1, __ intcon(11));
994
995 kit.set_control(__ IfTrue(iff));
996 if (kit.stopped()) {
997 final_merge->init_req(2, C->top());
998 final_size->init_req(2, C->top());
999 } else {
1000
1001 // int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
1002 RegionNode *r = new (C) RegionNode(3);
1003 kit.gvn().set_type(r, Type::CONTROL);
1004 Node *phi = new (C) PhiNode(r, TypeInt::INT);
1005 kit.gvn().set_type(phi, TypeInt::INT);
1006 Node *size = new (C) PhiNode(r, TypeInt::INT);
1007 kit.gvn().set_type(size, TypeInt::INT);
1008 Node* chk = __ CmpI(arg, __ intcon(0));
1009 Node* p = __ Bool(chk, BoolTest::lt);
1010 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_FAIR, COUNT_UNKNOWN);
1011 Node* lessthan = __ IfTrue(iff);
1012 Node* greaterequal = __ IfFalse(iff);
1013 r->init_req(1, lessthan);
1014 phi->init_req(1, __ SubI(__ intcon(0), arg));
1015 size->init_req(1, __ intcon(1));
1016 r->init_req(2, greaterequal);
1017 phi->init_req(2, arg);
1018 size->init_req(2, __ intcon(0));
1019 kit.set_control(r);
1020 C->record_for_igvn(r);
1021 C->record_for_igvn(phi);
1022 C->record_for_igvn(size);
1023
1024 // for (int i=0; ; i++)
1025 // if (x <= sizeTable[i])
1026 // return i+1;
1027
1028 // Add loop predicate first.
1029 kit.add_predicate();
1030
1031 RegionNode *loop = new (C) RegionNode(3);
1032 loop->init_req(1, kit.control());
1033 kit.gvn().set_type(loop, Type::CONTROL);
1034
1035 Node *index = new (C) PhiNode(loop, TypeInt::INT);
1036 index->init_req(1, __ intcon(0));
1037 kit.gvn().set_type(index, TypeInt::INT);
1038 kit.set_control(loop);
1039 Node* sizeTable = fetch_static_field(kit, size_table_field);
1040
1041 Node* value = kit.load_array_element(NULL, sizeTable, index, TypeAryPtr::INTS);
1042 C->record_for_igvn(value);
1043 Node* limit = __ CmpI(phi, value);
1044 Node* limitb = __ Bool(limit, BoolTest::le);
1045 IfNode* iff2 = kit.create_and_map_if(kit.control(), limitb, PROB_MIN, COUNT_UNKNOWN);
1046 Node* lessEqual = __ IfTrue(iff2);
1047 Node* greater = __ IfFalse(iff2);
1048
1049 loop->init_req(2, greater);
1050 index->init_req(2, __ AddI(index, __ intcon(1)));
1051
1052 kit.set_control(lessEqual);
1053 C->record_for_igvn(loop);
1054 C->record_for_igvn(index);
1055
1056 final_merge->init_req(2, kit.control());
1057 final_size->init_req(2, __ AddI(__ AddI(index, size), __ intcon(1)));
1058 }
1059
1060 kit.set_control(final_merge);
1061 C->record_for_igvn(final_merge);
1062 C->record_for_igvn(final_size);
1063
1064 return final_size;
1065 }
1066
1067 void PhaseStringOpts::int_getChars(GraphKit& kit, Node* arg, Node* char_array, Node* start, Node* end) {
1068 RegionNode *final_merge = new (C) RegionNode(4);
1069 kit.gvn().set_type(final_merge, Type::CONTROL);
1070 Node *final_mem = PhiNode::make(final_merge, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1071 kit.gvn().set_type(final_mem, Type::MEMORY);
1072
1073 // need to handle Integer.MIN_VALUE specially because negating doesn't make it positive
1074 {
1075 // i == MIN_VALUE
1076 IfNode* iff = kit.create_and_map_if(kit.control(),
1077 __ Bool(__ CmpI(arg, __ intcon(0x80000000)), BoolTest::ne),
1078 PROB_FAIR, COUNT_UNKNOWN);
1079
1080 Node* old_mem = kit.memory(char_adr_idx);
1081
1082 kit.set_control(__ IfFalse(iff));
1083 if (kit.stopped()) {
1084 // Statically not equal to MIN_VALUE so this path is dead
1085 final_merge->init_req(3, kit.control());
1086 } else {
1087 copy_string(kit, __ makecon(TypeInstPtr::make(C->env()->the_min_jint_string())),
1088 char_array, start);
1089 final_merge->init_req(3, kit.control());
1090 final_mem->init_req(3, kit.memory(char_adr_idx));
1091 }
1092
1093 kit.set_control(__ IfTrue(iff));
1094 kit.set_memory(old_mem, char_adr_idx);
1095 }
1096
1097
1098 // Simplified version of Integer.getChars
1099
1100 // int q, r;
1101 // int charPos = index;
1102 Node* charPos = end;
1103
1104 // char sign = 0;
1105
1106 Node* i = arg;
1107 Node* sign = __ intcon(0);
1108
1109 // if (i < 0) {
1110 // sign = '-';
1111 // i = -i;
1112 // }
1113 {
1114 IfNode* iff = kit.create_and_map_if(kit.control(),
1115 __ Bool(__ CmpI(arg, __ intcon(0)), BoolTest::lt),
1116 PROB_FAIR, COUNT_UNKNOWN);
1117
1118 RegionNode *merge = new (C) RegionNode(3);
1119 kit.gvn().set_type(merge, Type::CONTROL);
1120 i = new (C) PhiNode(merge, TypeInt::INT);
1121 kit.gvn().set_type(i, TypeInt::INT);
1122 sign = new (C) PhiNode(merge, TypeInt::INT);
1123 kit.gvn().set_type(sign, TypeInt::INT);
1124
1125 merge->init_req(1, __ IfTrue(iff));
1126 i->init_req(1, __ SubI(__ intcon(0), arg));
1127 sign->init_req(1, __ intcon('-'));
1128 merge->init_req(2, __ IfFalse(iff));
1129 i->init_req(2, arg);
1130 sign->init_req(2, __ intcon(0));
1131
1132 kit.set_control(merge);
1133
1134 C->record_for_igvn(merge);
1135 C->record_for_igvn(i);
1136 C->record_for_igvn(sign);
1137 }
1138
1139 // for (;;) {
1140 // q = i / 10;
1141 // r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
1142 // buf [--charPos] = digits [r];
1143 // i = q;
1144 // if (i == 0) break;
1145 // }
1146
1147 {
1148 // Add loop predicate first.
1149 kit.add_predicate();
1150
1151 RegionNode *head = new (C) RegionNode(3);
1152 head->init_req(1, kit.control());
1153 kit.gvn().set_type(head, Type::CONTROL);
1154 Node *i_phi = new (C) PhiNode(head, TypeInt::INT);
1155 i_phi->init_req(1, i);
1156 kit.gvn().set_type(i_phi, TypeInt::INT);
1157 charPos = PhiNode::make(head, charPos);
1158 kit.gvn().set_type(charPos, TypeInt::INT);
1159 Node *mem = PhiNode::make(head, kit.memory(char_adr_idx), Type::MEMORY, TypeAryPtr::CHARS);
1160 kit.gvn().set_type(mem, Type::MEMORY);
1161 kit.set_control(head);
1162 kit.set_memory(mem, char_adr_idx);
1163
1164 Node* q = __ DivI(NULL, i_phi, __ intcon(10));
1165 Node* r = __ SubI(i_phi, __ AddI(__ LShiftI(q, __ intcon(3)),
1166 __ LShiftI(q, __ intcon(1))));
1167 Node* m1 = __ SubI(charPos, __ intcon(1));
1168 Node* ch = __ AddI(r, __ intcon('0'));
1169
1170 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1171 ch, T_CHAR, char_adr_idx);
1172
1173
1174 IfNode* iff = kit.create_and_map_if(head, __ Bool(__ CmpI(q, __ intcon(0)), BoolTest::ne),
1175 PROB_FAIR, COUNT_UNKNOWN);
1176 Node* ne = __ IfTrue(iff);
1177 Node* eq = __ IfFalse(iff);
1178
1179 head->init_req(2, ne);
1180 mem->init_req(2, st);
1181 i_phi->init_req(2, q);
1182 charPos->init_req(2, m1);
1183
1184 charPos = m1;
1185
1186 kit.set_control(eq);
1187 kit.set_memory(st, char_adr_idx);
1188
1189 C->record_for_igvn(head);
1190 C->record_for_igvn(mem);
1191 C->record_for_igvn(i_phi);
1192 C->record_for_igvn(charPos);
1193 }
1194
1195 {
1196 // if (sign != 0) {
1197 // buf [--charPos] = sign;
1198 // }
1199 IfNode* iff = kit.create_and_map_if(kit.control(),
1200 __ Bool(__ CmpI(sign, __ intcon(0)), BoolTest::ne),
1201 PROB_FAIR, COUNT_UNKNOWN);
1202
1203 final_merge->init_req(2, __ IfFalse(iff));
1204 final_mem->init_req(2, kit.memory(char_adr_idx));
1205
1206 kit.set_control(__ IfTrue(iff));
1207 if (kit.stopped()) {
1208 final_merge->init_req(1, C->top());
1209 final_mem->init_req(1, C->top());
1210 } else {
1211 Node* m1 = __ SubI(charPos, __ intcon(1));
1212 Node* st = __ store_to_memory(kit.control(), kit.array_element_address(char_array, m1, T_CHAR),
1213 sign, T_CHAR, char_adr_idx);
1214
1215 final_merge->init_req(1, kit.control());
1216 final_mem->init_req(1, st);
1217 }
1218
1219 kit.set_control(final_merge);
1220 kit.set_memory(final_mem, char_adr_idx);
1221
1222 C->record_for_igvn(final_merge);
1223 C->record_for_igvn(final_mem);
1224 }
1225 }
1226
1227
1228 Node* PhaseStringOpts::copy_string(GraphKit& kit, Node* str, Node* char_array, Node* start) {
1229 Node* string = str;
1230 Node* offset = kit.load_String_offset(kit.control(), string);
1231 Node* count = kit.load_String_length(kit.control(), string);
1232 Node* value = kit.load_String_value (kit.control(), string);
1233
1234 // copy the contents
1235 if (offset->is_Con() && count->is_Con() && value->is_Con() && count->get_int() < unroll_string_copy_length) {
1236 // For small constant strings just emit individual stores.
1237 // A length of 6 seems like a good space/speed tradeof.
1238 int c = count->get_int();
1239 int o = offset->get_int();
1240 const TypeOopPtr* t = kit.gvn().type(value)->isa_oopptr();
1241 ciTypeArray* value_array = t->const_oop()->as_type_array();
1242 for (int e = 0; e < c; e++) {
1243 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1244 __ intcon(value_array->char_at(o + e)), T_CHAR, char_adr_idx);
1245 start = __ AddI(start, __ intcon(1));
1246 }
1247 } else {
1248 Node* src_ptr = kit.array_element_address(value, offset, T_CHAR);
1249 Node* dst_ptr = kit.array_element_address(char_array, start, T_CHAR);
1250 Node* c = count;
1251 Node* extra = NULL;
1252 #ifdef _LP64
1253 c = __ ConvI2L(c);
1254 extra = C->top();
1255 #endif
1256 Node* call = kit.make_runtime_call(GraphKit::RC_LEAF|GraphKit::RC_NO_FP,
1257 OptoRuntime::fast_arraycopy_Type(),
1258 CAST_FROM_FN_PTR(address, StubRoutines::jshort_disjoint_arraycopy()),
1259 "jshort_disjoint_arraycopy", TypeAryPtr::CHARS,
1260 src_ptr, dst_ptr, c, extra);
1261 start = __ AddI(start, count);
1262 }
1263 return start;
1264 }
1265
1266
1267 void PhaseStringOpts::replace_string_concat(StringConcat* sc) {
1268 // Log a little info about the transformation
1269 sc->maybe_log_transform();
1270
1271 // pull the JVMState of the allocation into a SafePointNode to serve as
1272 // as a shim for the insertion of the new code.
1273 JVMState* jvms = sc->begin()->jvms()->clone_shallow(C);
1274 uint size = sc->begin()->req();
1275 SafePointNode* map = new (C) SafePointNode(size, jvms);
1276
1277 // copy the control and memory state from the final call into our
1278 // new starting state. This allows any preceeding tests to feed
1279 // into the new section of code.
1280 for (uint i1 = 0; i1 < TypeFunc::Parms; i1++) {
1281 map->init_req(i1, sc->end()->in(i1));
1282 }
1283 // blow away old allocation arguments
1284 for (uint i1 = TypeFunc::Parms; i1 < jvms->debug_start(); i1++) {
1285 map->init_req(i1, C->top());
1286 }
1287 // Copy the rest of the inputs for the JVMState
1288 for (uint i1 = jvms->debug_start(); i1 < sc->begin()->req(); i1++) {
1289 map->init_req(i1, sc->begin()->in(i1));
1290 }
1291 // Make sure the memory state is a MergeMem for parsing.
1292 if (!map->in(TypeFunc::Memory)->is_MergeMem()) {
1293 map->set_req(TypeFunc::Memory, MergeMemNode::make(C, map->in(TypeFunc::Memory)));
1294 }
1295
1296 jvms->set_map(map);
1297 map->ensure_stack(jvms, jvms->method()->max_stack());
1298
1299
1300 // disconnect all the old StringBuilder calls from the graph
1301 sc->eliminate_unneeded_control();
1302
1303 // At this point all the old work has been completely removed from
1304 // the graph and the saved JVMState exists at the point where the
1305 // final toString call used to be.
1306 GraphKit kit(jvms);
1307
1308 // There may be uncommon traps which are still using the
1309 // intermediate states and these need to be rewritten to point at
1310 // the JVMState at the beginning of the transformation.
1311 sc->convert_uncommon_traps(kit, jvms);
1312
1313 // Now insert the logic to compute the size of the string followed
1314 // by all the logic to construct array and resulting string.
1315
1316 Node* null_string = __ makecon(TypeInstPtr::make(C->env()->the_null_string()));
1317
1318 // Create a region for the overflow checks to merge into.
1319 int args = MAX2(sc->num_arguments(), 1);
1320 RegionNode* overflow = new (C) RegionNode(args);
1321 kit.gvn().set_type(overflow, Type::CONTROL);
1322
1323 // Create a hook node to hold onto the individual sizes since they
1324 // are need for the copying phase.
1325 Node* string_sizes = new (C) Node(args);
1326
1327 Node* length = __ intcon(0);
1328 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1329 Node* arg = sc->argument(argi);
1330 switch (sc->mode(argi)) {
1331 case StringConcat::IntMode: {
1332 Node* string_size = int_stringSize(kit, arg);
1333
1334 // accumulate total
1335 length = __ AddI(length, string_size);
1336
1337 // Cache this value for the use by int_toString
1338 string_sizes->init_req(argi, string_size);
1339 break;
1340 }
1341 case StringConcat::StringNullCheckMode: {
1342 const Type* type = kit.gvn().type(arg);
1343 assert(type != TypePtr::NULL_PTR, "missing check");
1344 if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1345 // Null check with uncommont trap since
1346 // StringBuilder(null) throws exception.
1347 // Use special uncommon trap instead of
1348 // calling normal do_null_check().
1349 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1350 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1351 overflow->add_req(__ IfFalse(iff));
1352 Node* notnull = __ IfTrue(iff);
1353 kit.set_control(notnull); // set control for the cast_not_null
1354 arg = kit.cast_not_null(arg, false);
1355 sc->set_argument(argi, arg);
1356 }
1357 assert(kit.gvn().type(arg)->higher_equal(TypeInstPtr::NOTNULL), "sanity");
1358 // Fallthrough to add string length.
1359 }
1360 case StringConcat::StringMode: {
1361 const Type* type = kit.gvn().type(arg);
1362 if (type == TypePtr::NULL_PTR) {
1363 // replace the argument with the null checked version
1364 arg = null_string;
1365 sc->set_argument(argi, arg);
1366 } else if (!type->higher_equal(TypeInstPtr::NOTNULL)) {
1367 // s = s != null ? s : "null";
1368 // length = length + (s.count - s.offset);
1369 RegionNode *r = new (C) RegionNode(3);
1370 kit.gvn().set_type(r, Type::CONTROL);
1371 Node *phi = new (C) PhiNode(r, type);
1372 kit.gvn().set_type(phi, phi->bottom_type());
1373 Node* p = __ Bool(__ CmpP(arg, kit.null()), BoolTest::ne);
1374 IfNode* iff = kit.create_and_map_if(kit.control(), p, PROB_MIN, COUNT_UNKNOWN);
1375 Node* notnull = __ IfTrue(iff);
1376 Node* isnull = __ IfFalse(iff);
1377 kit.set_control(notnull); // set control for the cast_not_null
1378 r->init_req(1, notnull);
1379 phi->init_req(1, kit.cast_not_null(arg, false));
1380 r->init_req(2, isnull);
1381 phi->init_req(2, null_string);
1382 kit.set_control(r);
1383 C->record_for_igvn(r);
1384 C->record_for_igvn(phi);
1385 // replace the argument with the null checked version
1386 arg = phi;
1387 sc->set_argument(argi, arg);
1388 }
1389
1390 Node* count = kit.load_String_length(kit.control(), arg);
1391
1392 length = __ AddI(length, count);
1393 string_sizes->init_req(argi, NULL);
1394 break;
1395 }
1396 case StringConcat::CharMode: {
1397 // one character only
1398 length = __ AddI(length, __ intcon(1));
1399 break;
1400 }
1401 default:
1402 ShouldNotReachHere();
1403 }
1404 if (argi > 0) {
1405 // Check that the sum hasn't overflowed
1406 IfNode* iff = kit.create_and_map_if(kit.control(),
1407 __ Bool(__ CmpI(length, __ intcon(0)), BoolTest::lt),
1408 PROB_MIN, COUNT_UNKNOWN);
1409 kit.set_control(__ IfFalse(iff));
1410 overflow->set_req(argi, __ IfTrue(iff));
1411 }
1412 }
1413
1414 {
1415 // Hook
1416 PreserveJVMState pjvms(&kit);
1417 kit.set_control(overflow);
1418 C->record_for_igvn(overflow);
1419 kit.uncommon_trap(Deoptimization::Reason_intrinsic,
1420 Deoptimization::Action_make_not_entrant);
1421 }
1422
1423 Node* result;
1424 if (!kit.stopped()) {
1425
1426 // length now contains the number of characters needed for the
1427 // char[] so create a new AllocateArray for the char[]
1428 Node* char_array = NULL;
1429 {
1430 PreserveReexecuteState preexecs(&kit);
1431 // The original jvms is for an allocation of either a String or
1432 // StringBuffer so no stack adjustment is necessary for proper
1433 // reexecution. If we deoptimize in the slow path the bytecode
1434 // will be reexecuted and the char[] allocation will be thrown away.
1435 kit.jvms()->set_should_reexecute(true);
1436 char_array = kit.new_array(__ makecon(TypeKlassPtr::make(ciTypeArrayKlass::make(T_CHAR))),
1437 length, 1);
1438 }
1439
1440 // Mark the allocation so that zeroing is skipped since the code
1441 // below will overwrite the entire array
1442 AllocateArrayNode* char_alloc = AllocateArrayNode::Ideal_array_allocation(char_array, _gvn);
1443 char_alloc->maybe_set_complete(_gvn);
1444
1445 // Now copy the string representations into the final char[]
1446 Node* start = __ intcon(0);
1447 for (int argi = 0; argi < sc->num_arguments(); argi++) {
1448 Node* arg = sc->argument(argi);
1449 switch (sc->mode(argi)) {
1450 case StringConcat::IntMode: {
1451 Node* end = __ AddI(start, string_sizes->in(argi));
1452 // getChars words backwards so pass the ending point as well as the start
1453 int_getChars(kit, arg, char_array, start, end);
1454 start = end;
1455 break;
1456 }
1457 case StringConcat::StringNullCheckMode:
1458 case StringConcat::StringMode: {
1459 start = copy_string(kit, arg, char_array, start);
1460 break;
1461 }
1462 case StringConcat::CharMode: {
1463 __ store_to_memory(kit.control(), kit.array_element_address(char_array, start, T_CHAR),
1464 arg, T_CHAR, char_adr_idx);
1465 start = __ AddI(start, __ intcon(1));
1466 break;
1467 }
1468 default:
1469 ShouldNotReachHere();
1470 }
1471 }
1472
1473 // If we're not reusing an existing String allocation then allocate one here.
1474 result = sc->string_alloc();
1475 if (result == NULL) {
1476 PreserveReexecuteState preexecs(&kit);
1477 // The original jvms is for an allocation of either a String or
1478 // StringBuffer so no stack adjustment is necessary for proper
1479 // reexecution.
1480 kit.jvms()->set_should_reexecute(true);
1481 result = kit.new_instance(__ makecon(TypeKlassPtr::make(C->env()->String_klass())));
1482 }
1483
1484 // Intialize the string
1485 if (java_lang_String::has_offset_field()) {
1486 kit.store_String_offset(kit.control(), result, __ intcon(0));
1487 kit.store_String_length(kit.control(), result, length);
1488 }
1489 kit.store_String_value(kit.control(), result, char_array);
1490 } else {
1491 result = C->top();
1492 }
1493 // hook up the outgoing control and result
1494 kit.replace_call(sc->end(), result);
1495
1496 // Unhook any hook nodes
1497 string_sizes->disconnect_inputs(NULL, C);
1498 sc->cleanup();
1499 }